Twitter’s founder and Chief Executive Jack Dorsey has pledged to donate $1bn to help the fight against Covid-19.

Announcing the donation on Twitter, Dorsey said that the $1bn would go towards funding coronavirus research to help “disarm this pandemic”.

Dorsey, also founder of payments company Square, tweeted that he was donating $1bn of Square shares to a charitable fund, called Start Small, to “fund global Covid-19 relief”.

Dorsey, 43, said the donation was equivalent to about “28% of my wealth”. Dorsey has a fortune of about $3.9bn, according to the Bloomberg Billionaires Index.

Dorsey cofounded Twitter in 2006 with Ev Williams, Biz Stone and Noah Glass, and was CEO until 2008. He returned in 2015. Before gravitating to tech, he was a certified masseur and dabbled in fashion design.

Twitter announced last month that it will remove tweets that run the risk of causing harm by spreading dangerous misinformation about Covid-19 on its site. The move comes amid widespread criticism that social media companies are not doing enough to tackle misinformation around the novel coronavirus on their sites.